Cruise control system

ABSTRACT

A cruise control system for use in connection with a control arm linked to a swash plate that is moveable to provide the swash plate with a plurality of non-discrete angular orientations to affect fluid displacement of a hydraulic pump and a return to neutral mechanism for moving the control arm from a driving position to a position in which the swash plate does not affect fluid displacement of the hydraulic pump. The cruise control system includes a cruise control arm having a portion occupying a plane in common with a portion of the control arm. The cruise control arm is moveable to place the portion of the cruise control arm into contact with the portion of the control arm to prevent the control arm from moving from one of a plurality of non-discrete forward driving positions to the neutral position under the influence of the return to neutral mechanism.

BACKGROUND OF THE INVENTION

[0001] This invention relates generally to hydrostatic transmissionsand, more particularly, to a cruise control system for use in connectionwith a hydrostatic transmission.

[0002] Hydrostatic transmissions (“HSTs”), including integratedhydrostatic transmissions (“IHTs”), are well known in the art and aremore fully described in, among others, U.S. Pat. No. 5,314,387, which isincorporated herein by reference in its entirety. Generally, an HSTincludes a center section or the like on which is mounted a hydraulicpump and a hydraulic motor. The hydraulic pump and the hydraulic motoreach carry a plurality of reciprocating pistons that are in fluidcommunication through porting formed in the center section. As thehydraulic pump rotates, the pump pistons move axially as they bearagainst an adjustable swash plate where the angular orientation of theswash plate affects the degree of axial movement of the pump pistons.The movement of the pump pistons forces a hydraulic fluid through theporting to the motor pistons which causes the motor pistons to be forcedagainst a thrust bearing to thereby rotate the hydraulic motor. As thehydraulic motor rotates, hydraulic fluid is returned to the hydraulicpump through the porting. In this manner, the rotation of the hydraulicpump is translated to the hydraulic motor to drive one or more axles ofa riding lawn mower, small tractor, or the like.

[0003] For maintaining a desired hydrostatically driven vehicle speed,various speed control systems are known in the art. By way of example,speed control systems are disclosed in U.S. Pat. Nos. 4,620,575,4,553,626, 4,281,737, 4,727,710, 5,228,360, and 6,202,779. While suchknown speed control mechanisms do work for their intended purpose, theydo suffer disadvantages related to their size, cost, and complexity.Accordingly, it is an object of the present invention to provide animproved cruise control system.

SUMMARY OF THE INVENTION

[0004] In accordance with the object of this invention, a cruise controlsystem is disclosed which is selectively engaged and disengaged by anoperator independent of the function of the control arm of the hydraulicpump. The cruise control system allows the control arm to be maintainedin a plurality of non-discrete positions. Also disclosed is a brakeactuated return to neutral mechanism that may be used to disengage thecruise control mechanism by means of a linkage connected to a brakepedal, handle, or the like.

[0005] A better understanding of the objects, advantages, features,properties and relationships of the invention will be obtained from thefollowing detailed description and accompanying drawings which set forthillustrative embodiments that are indicative of the various ways inwhich the principles of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] For a better understanding of the invention, reference may be hadto preferred embodiments shown in the following drawings in which:

[0007]FIG. 1 illustrates an internal view of an exemplary embodiment ofa hydrostatic transmission;

[0008]FIG. 2 illustrates a side view of an exemplary cruise controlsystem installed on the hydrostatic transmission of FIG. 1 in which thecruise control system is in a deactivated position with the hydrostatictransmission in a neutral position;

[0009]FIG. 3 illustrates the cruise control system of FIG. 2 in adeactivated position with the hydrostatic transmission in a forwarddriving position and wherein a portion of a brake arm has been removedto provide an unobstructed view of certain elements thereof;

[0010]FIG. 4 illustrates the cruise control system of FIG. 2 in anactivated position with the hydrostatic transmission in a forwarddriving position and wherein a portion of a brake arm has been removedto provide an unobstructed view of certain elements thereof;

[0011]FIG. 5 illustrates an exploded view of the cruise control systemof FIG. 2;

[0012]FIG. 6 illustrates the hydrostatic transmission and cruise controlsystem of FIG. 2 installed on an exemplary vehicle;

[0013]FIG. 7 illustrates a side view of a further, exemplary cruisecontrol system installed on a further, exemplary hydrostatictransmission in which the cruise control system is in a deactivatedposition, the hydrostatic transmission is in a neutral position, and thebrake activated return to neutral mechanism is deactivated;

[0014]FIG. 8 illustrates the cruise control system of FIG. 7 in adeactivated position with the hydrostatic transmission in a forwarddriving position and wherein a bearing cap has been removed to providean unobstructed view of certain elements thereof;

[0015]FIG. 9 illustrates the cruise control system of FIG. 7 in anactivated position with the hydrostatic transmission in a forwarddriving position and wherein a bearing cap has been removed to providean unobstructed view of certain elements thereof;

[0016]FIG. 10 illustrates the cruise control system of FIG. 9 after thebrake has been activated;

[0017]FIG. 11 illustrates an isometric view of the cruise control systemillustrated in FIG. 7; and

[0018]FIG. 12 illustrates an isometric view of the cruise control systemillustrated in FIG. 10.

DETAILED DESCRIPTION

[0019] Turning now to the figures, wherein like reference numerals referto like elements, there is illustrated in FIG. 1 an exemplaryhydrostatic transmission in the form of an IHT 10. As will be understoodby those of skill in the art, the IHT 10 generally operates on theprinciple of an input shaft 12 rotatably driving a hydraulic pump 14which, through the action of its pump pistons, pushes hydraulic fluid toa hydraulic motor (not shown) through porting formed in a center section20 to cause the rotation of the hydraulic motor. The rotation of thehydraulic motor causes the rotation of a motor shaft 22 which rotationis eventually transferred through a gearing system or the like to driveone axle shaft (in the case of a zero-turn hydrostatic transaxle) or apair of axle shafts (as illustrated in FIG. 6). A motive force from, forexample, an engine may be supplied directly to the input shaft 12 orindirectly by means of a pulley to drive the hydraulic pump 14. For amore detailed description of the principles of operation of such ahydrostatic transmission, the reader is referred to U.S. Pat. Nos.5,201,692, 6,322,474 and 6,122,996 which are incorporated herein byreference in their entirety.

[0020] To support the components of the IHT 10, the IHT 10 is providedwith a housing 24. In the illustrated example, the housing 24 comprisesa first side housing section and a second side housing section that arejoined along a substantially vertical junction surface. Extending fromthe top of the housing 24 is the input shaft 12. Meanwhile, the axleshafts in the illustrated example would extend from both the first sidehousing section and the second side housing section. Thus, in theillustrated, exemplary IHT 10, the axis of the axle shafts would begenerally perpendicular to the substantially vertical junction surface.Similarly, in the illustrated embodiment, since the center section 20 isgenerally “L-shaped,” the plane of the pump running surface of thecenter section 20 is generally perpendicular to the substantiallyvertical junction surface while the plane of the motor running surfaceof the center section 20 is generally parallel to the substantiallyvertical junction surface. The axis of the motor shaft 22 would begenerally parallel to the axis of the axle shafts and perpendicular tothe axis of the input shaft 12. It is to be understood, however, thatthis arrangement is merely illustrative and that the housing and/or IHToperating components can be otherwise arranged without departing fromthe scope of this invention.

[0021] For placing the hydraulic pump 14 in fluid communication with thehydraulic motor, the center section 20 includes hydraulic porting. Thehydraulic porting is in further fluid communication with a source ofmakeup fluid, such as a fluid sump or a charge gallery. Generally, thehydraulic porting comprises a high pressure side through which fluidmoves from the hydraulic pump 14 to the hydraulic motor and a lowpressure side through which fluid returns from the hydraulic motor tothe hydraulic pump 14. A filter assembly 18 may be positioned adjacentthe center section 20, intermediate the sump and the hydraulic porting,to minimize the introduction of impurities, such as metal shavings, intothe hydraulic circuit when makeup fluid is drawn into the hydrauliccircuit.

[0022] To adjust the amount of oil that is forced from the hydraulicpump 14 to the hydraulic motor via the high pressure side hydraulicporting, the IHT 10 includes a moveable swash plate 13 against which thepump pistons travel. The direction of rotation of the hydraulic pump 14is fixed by the rotation of the input shaft 12 and, as such, thehydraulic pump 14 is nearly always rotated in one direction. As will beunderstood by those of ordinary skill in the art, the swash plate 13 maybe moved to a variety of positions to vary the stroke of the pumppistons and the direction of rotation of the hydraulic motor. Generally,as the angular orientation of the swash plate 13 is varied in onedirection from the neutral position the axial displacement or stroke ofthe pump pistons is varied, which then drives the hydraulic motor in adirection determined by the hydraulic porting at a speed that is relatedto the volume of the fluid displaced by the pump pistons taking intoconsideration the efficiency of the system. In the neutral position, theswash plate 13 does not function to axially displace the pump pistons.

[0023] Rotation of the hydraulic motor results from the motor pistonsmoving against a thrust bearing under the influence of the hydraulicfluid. As the angular orientation of the swash plate 13 is decreased topass through the neutral position, the direction of rotation of thehydraulic motor is reversed and the speed of the hydraulic motor isagain influenced by the volume of fluid displaced by the pump pistons.Since the speed of rotation of the hydraulic motor is dependent upon theamount of hydraulic fluid pumped thereinto by the hydraulic pump 14 andthe direction of rotation of the hydraulic motor is dependent upon theangular orientation of the swash plate 13, the angular orientation ofthe swash plate 13 is seen to control the speed and direction ofrotation of the hydraulic motor and, as will be apparent, the speed anddirection of rotation of the axle shaft(s) 23.

[0024] For moving the swash plate 13, the swash plate 13 has trunnionarms 25 and 27 that are rotatably supported in the housing 24 of the IHT10. Rotation of a trunnion arm 25 (or 27) changes the angularorientation of the swash plate 13 with respect to the pump pistons. Torotate the trunnion arm 25 and, accordingly, move the swash plate 13, acontrol arm 30 is coupled to the trunnion arm 25. As illustrated in FIG.6, the control arm 30 may be connected, via a driving link 32 or thelike, to a lever, pedal, etc. (collectively referred to as a pedal 34)provided on a vehicle 36 whereby movement of the pedal 34 is translatedto the control arm 30 to cause the rotation of the trunnion arm 25 andmovement of the swash plate 13.

[0025] To return the HST 10 from a driving position (i.e., one in whichthe swash plate 13 has an angular orientation that causes axialdisplacement of the pump pistons) to the neutral position, a return toneutral (“RTN”) mechanism 38 may be mounted to the housing 24 thatcooperatively engages the control arm 30. Generally, as illustrated inFIGS. 2-5, an exemplary RTN mechanism 38 comprises a return arm 40 thatis rotationally mounted to the housing 24. The return arm 40 furthercomprises a generally arcuate surface that engages, for example, abearing 42 that is mounted on or otherwise formed as part of the controlarm 30, as illustrated in FIG. 5. A spring 43 serves to bias therotationally mounted return arm 40 against the bearing 42.

[0026] In operation, when the control arm 30 is moved from the neutralposition, illustrated in FIG. 2, to a driving position, illustrated asthe forward driving position in FIG. 3, the control arm bearing 42 movesagainst the arcuate surface of the return arm 40 which causes the returnarm 40 to rotate against the bias of the spring 43. When the control arm30 is released, for example when the pedal 34 is released, the biasingforce of the spring 43 causes the return arm 40 to rotate in a directiontoward the control arm 30. This inward movement of the return arm 40causes the arcuate surface of the return arm 40 to force the control armbearing 42 along the arcuate surface. The return arm 40 continues tomove in this manner until further movement of the return arm 40 isinhibited, i.e., the control arm bearing 42 becomes positioned in thewell 45 of the arcuate return arm surface. When the control arm bearing42 stops moving under the influence of the biased return arm 40, thecontrol arm 30 will have been moved to a position that places the swashplate 13 in the neutral position. It will be appreciated that thearcuate nature of the engaging surface of the return arm 40 allows theRTN mechanism 38 to function when the control arm 30 is moved intoeither the forward and reverse driving directions.

[0027] For use in maintaining engagement between the return arm 40 andbearing 42, a cap 44 may be affixed adjacent to bearing 42 thatfunctions to laterally constrain the return arm 40 on bearing 42. Todampen movement of the control arm 30 as it is being moved into aforward or reverse drive position and when the control arm 30 is beingreturned to the neutral position under the influence of the RTNmechanism 38, the control arm 30 may be attached to a dampeningmechanism 48. In the illustrated example, the dampening mechanism 48comprises a two-way piston 50 attached at one end to the housing 24 viaa piston bracket 51 and at the other end to the control arm 30. Thetwo-way action of the piston 50 allows movement of the control arm 30 tobe dampened when being moved to or from the neutral position.Alternatively, the dampening mechanism 48 may be linked to the RTNmechanism 38.

[0028] For use in maintaining a relative position of the control arm 30and, accordingly, an angular orientation of the swash plate 13, tothereby generally maintain a desired hydrostatically driven vehiclespeed when the control arm 30 is released (e.g., the pedal 34 isreleased), a cruise control mechanism 39 may be mounted to the housing24 that is adapted to cooperatively engage the control arm 30.Generally, as illustrated in FIGS. 2-5, an exemplary cruise controlmechanism 39 comprises a pivotally mounted cruise control arm 52 havinga first arm portion 52 a and a second, opposite arm portion 52 b. Thefirst arm portion 52 a may be connected via a linkage 54, for example,to a cruise control lever 56 or the like. As will be appreciated fromthe description that follows, the cruise control lever 56 may be movedto rotate the cruise control arm 52, via the linkage 54, into anon-discrete position in which the cruise control arm 52 engages thecontrol arm 30 to inhibit movement of the control arm 30 under theinfluence of the RTN mechanism 38, as illustrated in FIG. 4. The cruisecontrol lever 56 may also be moved to rotate the cruise control arm 52into an inactive position, as illustrated in FIGS. 2 and 3. In theinactive position, the cruise control arm 52 will not be in a positionto interfere with the functioning of the RTN mechanism 38 describedabove. It is further preferred that, when in the fully inactive cruisecontrol position, the control arm 30 is free to move over its full rangeof motion without contact with the cruise control arm 52. While thecruise control arm 52 is illustrated as pivoting about the trunnion arm25, it will be appreciated that other pivot points can be provided and,as such, the illustrated arrangement is not intended to be limiting.

[0029] For engaging the control arm 30 to thereby effect cruise control,the cruise control arm 52 may be configured such that the cruise controlarm portion 52 a has a portion 52 c that falls within a plane generallyoccupied by the control arm 30. While the portion 52 c is illustrated asa generally flat extension, it will be appreciated that the portion 52 ccan be formed as a protuberance or other feature that is arranged tofall at least partly within the same general plane as the control arm30. In this manner, as illustrated in FIG. 4, rotation of the cruisecontrol arm 52 functions to place the portion 52 c of the cruise controlarm 52 at a location in which the portion 52 c is capable of contactinga side of the control arm 30.

[0030] To maintain a position of engagement between the cruise controlarm portion 52 c and the control arm 30 against the biasing force of theRTN mechanism 38, the cruise control arm portion 52 a may restrained bya friction pack 66. Such a friction pack 66 may generally include anoptional, axially adjustable wedge 68 (which may be used to adjust theposition of the cruise control arm 52 in particular portion 52 c-withrespect to the control arm 30) and frictional elements 73 and 74 betweenwhich the cruise control arm 52 is positioned. The frictional elements73 and 74 may be constructed from plastic or nylon. A bolt 70, nut 72,and washer 69, or like component(s), may be used to vary the degree ofthe frictional engagement imparted by the frictional elements 73 and 74upon the cruise control arm 52 by compressing spring 79 against a washer71 which then compresses frictional elements 73 and 74 against thecruise control arm portion 52 b. It will be appreciated that, since thefriction pack 66 functions to apply a force upon the cruise control arm52 that is sufficient to inhibit movement of the cruise control arm 52under the influence of a force applied via the control arm 30 and RTNmechanism 38, the cruise control feature can be disabled by simplyloosening the friction pack 66, i.e., to lessen the frictionalengagement to the point where the frictional force applied to the cruisecontrol arm 52 is insufficient to withstand a force applied via thecontrol arm 30 and RTN mechanism 38. For more detail regarding such afriction pack, the reader is referred to U.S. Pat. No. 6,253,637 that isincorporated herein by reference in its entirety. While theaforementioned discussion details a specific configuration of anexemplary friction pack, it will be appreciated that other friction packconfigurations may be readily adapted to mate with the cruise controlarm 52. As such, the described friction pack configuration should not beread as being required.

[0031] It will be further appreciated that the cruise control mechanism38 illustrated in FIGS. 1-6 only functions to generally maintain adesired hydrostatically driven vehicle speed in the forward drivingdirection. Thus, in illustrated example, the cruise control arm 52 onlyfunctions to inhibit the movement of the control arm 30 when the controlarm 30 is being forced in the counter-clockwise direction (i.e., in thedirection of the cruise control arm 52) by the RTN mechanism 38. Thecruise control arm 52 will not inhibit the movement of the control arm30 when the control arm 30 is being forced in the clockwise direction(i.e., in a direction away from the cruise control arm 52) by the RTNmechanism 38. The cruise control mechanism 38 does, however, allow thecruise control arm 52 to be positioned in any of a plurality ofnon-discrete positions allowing for a plurality of non-discrete forwarddriving speeds to be generally maintained.

[0032] To limit the range of motion of the control arm 30, the controlarm 30 may be provided with a slot 76 in which is disposed a pin 77 orthe like that is fixedly secured to the housing 24. In this manner, oneend of the slot 76 will engage the pin 77 when the control arm 30attains the allowed, full forward driving position (illustrated in FIG.3) and the other end of the slot 76 will engage the pin 77 when thecontrol arm 30 attains the allowed, full reverse driving position.Similarly, to limit the range of motion of the cruise control arm 52,the cruise control arm 52 may be provided with a slot 78 in which isdisposed the mounting bolt 70. Accordingly, one end of the slot 78 willengage the bolt 70 when the cruise control arm 52 attains the allowed,fully active cruise control position (illustrated in FIG. 4) and theother end of the slot 78 will engage the bolt 70 when the cruise controlarm 52 attains the allowed, fully inactive cruise control position(illustrated in FIGS. 2 and 3).

[0033] To slow and/or stop movement of the motor shaft 22 and,accordingly, movement of the axle shaft(s) 23, for example, to preventfree-wheeling of the vehicle 36, a parking brake mechanism 80 may bemounted to the housing 24 so as to engage the motor shaft 22. It will beappreciated that the brake mechanism 80 may be a disc brake mechanism,as illustrated in FIGS. 1-5, a cogged parking brake (not illustrated),or the like. Since such parking brake mechanisms are well known, theywill not be discussed in greater detail herein for the sake of brevity.

[0034] Illustrated in FIGS. 7-12 is a further embodiment of a cruisecontrol system 39′ that operates in connection with a brake activatedRTN 38′. The brake activated RTN 38′ functions to return the HST 10′from a driving position to the neutral position and generally comprisesa return arm 40′ that is rotationally mounted to the housing 24′. Thereturn arm 40′ again comprises a generally arcuate surface that engages,for example, a bearing 42 that is mounted on or otherwise formed as partof a control arm 30′ that is linked to the swash plate 13. Asparticularly illustrated in FIGS. 11 and 12, a spring 43′ is providedfor biasing the rotationally mounted return arm 40′ against the bearing42. To this end, one end of the spring 43′ is attached to an end of thereturn arm 40′ while the other end of the spring 43′ is attached to thehousing 24′, for example, via a mounting bracket 24 a.

[0035] In operation, when the control arm 30′ is moved from the neutralposition, illustrated in FIG. 7, to a driving position, illustrated asthe forward driving position in FIG. 8, the control arm bearing 42 movesagainst the arcuate surface of the return arm 40′ which causes thereturn arm 40′ to rotate against the bias of the spring 43′. When thecontrol arm 30′ is released, for example when the pedal 34 (connectedvia a linkage to control arm portion 30′a) is released, the biasingforce of the spring 43′ causes the return arm 40′ to rotate in adirection toward the control arm 30′. This inward movement of the returnarm 40′ causes the arcuate surface of the return arm 40′ to force thecontrol arm bearing 42 along the arcuate surface. The return arm 40′continues to move in this manner until further movement of the returnarm 40′ is inhibited, i.e., the control arm bearing 42 becomespositioned in the well 45′ of the arcuate return arm surface. When thecontrol arm 30′ stops moving in this manner, the control arm 30′ willhave been moved to a position that places the swash plate 13 in theneutral position. The position of the well 45′ corresponding to neutralmay be adjusted by means of a return arm neutral adjusting cam 93.

[0036] For use in maintaining engagement between the return arm 40′ andbearing 42, a cap 44, shown in FIG. 7, may be affixed adjacent tobearing 42 that functions to laterally constrain the return arm 40′ onbearing 42. This cap 44 has been removed from FIGS. 810 and 12 so as toallow a view of the engagement between the bearing 42 and the return arm40′. To dampen movement of the control arm 30′ as it is being moved intoa forward or reverse drive position and when the control arm 30′ isbeing returned to the neutral position under the influence of the RTN38′, a dampening mechanism 48′ may be attached to control arm portion30′b.

[0037] For use in maintaining a relative position of the control arm 30′and, accordingly, an angular orientation of the swash plate 13, tothereby generally maintain a desired hydrostatically driven vehiclespeed when the control arm 30′ is released, a cruise control mechanism39′ may be mounted to the housing 24′ that is adapted to cooperativelyengage the control arm 30′. Generally, the cruise control system 39′comprises a cruise control arm 52′ which, by way of example only and asillustrated in FIGS. 7-12, is pivotally mounted over the trunnion arm.The cruise control arm 52′ has a first arm portion 52′a, a second armportion 52′b, a third arm portion 52′c, and a fourth arm portion 52′d.The first arm portion 52′a or the fourth arm portion 52′d may beconnected, for example, via a linkage to a cruise control lever or thelike. The cruise control lever may then be moved to rotate the cruisecontrol arm 52′ into a non-discrete position in which the cruise controlarm 52′ engages the control arm 30′ to inhibit movement of the controlarm 30′ under the influence of the RTN mechanism 38′, as illustrated inFIG. 9. The cruise control lever may also be moved to rotate the cruisecontrol arm 52′ into an inactive position, illustrated in FIGS. 7 and 8.In the inactive position, the cruise control arm 52′ will not be in aposition to interfere with the functioning of the RTN mechanism 38′. Itis again preferred that, when in the fully inactive cruise controlposition, the control arm 30′ is free to move over its full range ofmotion without contact with the cruise control arm 52′.

[0038] For engaging the control arm 30′ to thereby effect cruisecontrol, the cruise control arm 52′ may be configured such that thecruise control arm portion 52′a has a portion 52′c that falls within aplane generally occupied by the control arm 30′. While the portion 52′cis illustrated as being a generally flat extension of the cruise controlarm 52′, it will be appreciated that the portion 52′c can be formed as aprotuberance or other feature that is arranged to fall at leastpartially within the same general plane as the control arm 30′. As willbe appreciated, a protuberance 30′c may be formed as part of or attachedto the control arm 30′ to achieve a similar function as a protuberanceassociated with the cruise control arm 52′. Still further, there may beprovided overlapping protuberances formed on the control arm 30′ andcruise control arm 52′. In accordance with any of these arrangements,rotation of the cruise control arm 52′ functions to place the portion52′c of the cruise control arm 52′ at a location in which the portion52′c is capable of contacting a side of the control arm 30′ as isillustrated in FIG. 9.

[0039] To maintain a position of engagement between the cruise controlarm 52′ and the control arm 30′ against the biasing force of the RTNmechanism 38′, the cruise control arm portion 52′b may be restrained bya friction pack 66′. This frictional force may be overcome, however,when a brake is actuated as will be described hereinafter.

[0040] It will be again appreciated that the cruise control mechanism38′ illustrated in FIGS. 7-12 only functions to generally maintain adesired hydrostatically driven vehicle speed in the forward drivingdirection. Thus, in the example illustrated in FIGS. 7-11, the cruisecontrol arm 52′ only functions to inhibit movement of the control arm30′ when the control arm 30′ is being forced in the clockwise directionby the RTN mechanism 38′. The cruise control arm 52′ will not inhibitmovement of the control arm 30′ when the control arm is being forced inthe counter-clockwise direction by the RTN mechanism 38′. The cruisecontrol mechanism 38′ does, however, allow the cruise control arm 52′ tobe positioned in any of a plurality of non-discrete positions allowingfor a plurality of non-discrete forward driving speeds to be generallymaintained.

[0041] To slow and/or stop movement of the motor shaft 22 and,accordingly, movement of the axle shaft(s) 23′, for example, to preventfree-wheeling of the vehicle 36, a brake mechanism 80′ may be mounted tothe housing 24′ so as to engage the motor shaft 22. As illustrated inFIGS. 7-12, the brake mechanism 80′ may be a disc brake mechanism thatis cooperatively mounted to the motor shaft 22. For use in returning thecontrol arm 30′ to the neutral position, the brake mechanism 80′ isfurther adapted to cooperate with the RTN mechanism 39′. As will bediscussed hereinafter, the control arm 30′ may be returned to theneutral position when the brake is actuated without requiring the cruisecontrol mechanism 38′ to be separately disengaged.

[0042] For use in actuating the brake mechanism 80′, the brake mechanism80′ may be attached via a linkage 90, illustrated in FIG. 7, to a brakepedal, brake lever, or the like. More specifically, the linkage 90 isrotationally attached to a rotationally mounted brake return arm 41 suchthat movement of the linkage 90 causes the brake return arm 41 to drivethe bearing 42 to force the control arm 30′ to neutral. For thispurpose, the brake return arm 41 is provided with angled surfaces 41 athat functions to drive the bearing 42 (from either the forward orreverse driving positions) towards the well 45′ of the return arm 40′ asthe brake return arm 41 is moved towards the bearing 42. During suchmovement, the biasing force of spring 43′ maintains the return arm 40′against the bearing 42. Furthermore, if the control arm 30′ is beingdriven from a forward driving position and the cruise control 39′ isactivated, movement of the control arm 30′ under the force of the brakereturn arm 41 also moves the cruise control arm 52′ with which thecontrol arm 30′ is in engagement. As noted previously, the driving forceof the linkage 90 and brake return arm 41 is sufficient to overcome therestraining forces of the friction pack 66′ acting upon the cruisecontrol arm 52′. As movement of the brake return arm 41 continues inthis manner, the brake return arm 41 will move the control arm 30′ untilthe bearing 42 is seated in the well 45′ of the return arm 40′ and awell 41 b formed in the brake return arm 41. As will be apparent fromFIG. 10, when the brake is actuated the well 41 b functions to engagethe bearing 42 so as to prevent movement of the control arm 30′ tomaintain the control arm 30′ in the neutral position.

[0043] For actuating the brake mechanism 80′, the brake return arm 41 isconnected via a link 96 to a rotationally mounted brake actuating arm 94that is adapted to drive, for example, brake disc 82 into engagementwith a frictional element (not visible). The link 96 is rotationallymounted to the brake return arm 41 at one end and passes through anopening in the brake actuating arm 94 where a spring 98 is positionedbetween the brake actuating arm 94 and the opposite end of the link 96.A nut and washer combination or the like 97 may be provided at the endof the link 96 to provide a restraining surface that engages the end ofthe spring 98 that is opposite the brake actuating arm 94. In thismanner, when the brake link 90 and the brake return arm 41 are moved,seen for example by comparing FIGS. 9 and 10, the link 96 is driven tocause compression of the spring 98 which, in turn, exerts an increasingamount of pressure upon the brake actuating arm 94 so as to rotate thebrake actuating arm 94 to drive the brake disc 82 into engagement withthe frictional element. In particular, by the time the bearing 42 is inthe neutral position, the compression force of the spring 98 on thebrake actuating arm 94, resulting from the movement of the brake returnarm 41 and link 96, is sufficient to put the brake disc 82 into a stateof engagement with the frictional element that will maintain the vehiclein a stopped condition. When the brake lever and linkage 90 arereleased, a spring 100, attached between the housing 24 and brake returnarm 41, functions (in cooperation with spring 98 and spring 106discussed hereinafter) to return the brake return arm 41, andaccordingly the brake mechanism 80′, to the disengaged state.

[0044] For allowing the IHT 10′ to freewheel, the IHT 10′ may beprovided with a bypass mechanism as described in U.S. Pat. No. 6,374,604which is incorporated herein by reference in its entirety. The bypassmechanism is preferably provided with a bypass latching arm 102 thatcooperates to engage and hold a bypass arm 104 used to drive the bypassmechanism until such time as the bypass latch is defeated, for example,when the brake is activated so as to allow for proper functioning of theIHT 10′. As illustrated in FIGS. 11 and 12, the bypass latching arm 102is rotationally mounted to the housing 24′ and has one end that isadapted to be driven by the brake actuating arm 94 against the bias of aspring 106. To this end, the bypass latching arm 102 includes an opening108 through which the link 96 passes and a surface that is in abuttedengagement with the brake actuating arm 94. In this manner, when thebrake is actuated, illustrated in FIG. 12, the brake actuating arm 94moves the bypass latching arm 102 causing the bypass latching arm 102 torotate away from the bypass arm 104 which then allow bypass arm spring110 to move the bypass arm 104 into a disengaged or non-bypass position.When the brake is deactivated, illustrated in FIG. 11, the biasingspring 106 causes the bypass latching arm 102 to rotate into a positionthat would allow the bypass arm 104 to be move into engagement with thebypass latching arm 102, via a separate linkage not illustrated. It willalso be seen that, when the brake lever and linkage are released, thecompression of spring 98 against the brake arm 94 is also removed whichthen allows the force of spring 106 to be transferred through bypasslatch arm 102 to brake arm 94 to thereby release engagement of the brakedisk 82 from the frictional element. Since the brake arm return spring100 may come in a variety of configuration that may be used to provide asimilar function, this description is not intended to be read aslimiting.

[0045] For latching the bypass arm 104 to maintain the bypass condition,the bypass latching arm 102 includes a grooved portion 102 a adapted tomate with a corresponding feature 104 a provided to the bypass arm 104.To allow the bypass arm 104 to be rotated into a position of engagementwith the bypass latching arm 102, the bypass latching arm 102 isprovided with a cammed surface 102 b leading to the grooved portion 102a. In this manner, when the bypass arm 104 is rotated from anon-activated position to an activated position (when the brake isreleased so that bypass latching arm 102 is appropriately positioned),the bypass arm feature 104 a interacts with the cammed surface 102 b tocause the bypass latching arm 102 to rotate against the bias of thespring 106 to allow the bypass arm 104 to move relative to the bypasslatching arm 102. Movement in this manner continues until the bypass armfeature 104 a seats in the grooved portion 102 a and the spring 106returns the bypass latching arm 102 to a position where the groovedportion 102 a cooperates with the bypass arm feature 104 a to maintainthe position of the bypass arm 104.

[0046] While specific embodiments of the invention have been describedin detail, it will be appreciated by those skilled in the art thatvarious modifications and alternatives to those details could bedeveloped in light of the overall teachings of the disclosure.Accordingly, the particular arrangements of the return to neutralmechanism, dampening mechanism, brake mechanism, etc. disclosed aremeant to be illustrative only and not limiting as to the scope of theinvention which is to be given the full breadth of the appended claimsand any equivalents thereof.

What is claimed is:
 1. An assembly, comprising: a hydraulic pump; aswash plate; a control arm linked to the swash plate and moveable toprovide the swash plate with a plurality of non-discrete angularorientations with respect to the hydraulic pump; a return to neutralmechanism for moving the control arm from a driving position to aneutral position; and a cruise control arm moveable to a plurality ofnon-discrete positions having a portion occupying a plane in common witha portion of the control arm, wherein the cruise control arm is moveableto place the portion of the cruise control arm in contact with theportion of the control arm to prevent the control arm from moving fromone of a plurality of non-discrete forward driving positions to theneutral position under the influence of the return to neutral mechanism.2. The assembly as recited in claim 1, wherein the return to neutralmechanism comprises a biased return arm that contacts the control arm.3. The assembly as recited in claim 1, further comprising a frictionpack for frictionally engaging the cruise control arm with a forcesufficient to overcome a force applied to the control arm by the returnto neutral mechanism.
 4. The assembly as recited in claim 1, wherein theportion of the cruise control arm comprises a generally flat surface ofthe cruise control arm.
 5. The assembly as recited in claim 1, whereinthe portion of the cruise control arm comprises a protuberance of thecruise control arm.
 6. The assembly as recited in claim 1, wherein theportion of the control arm comprises a protuberance of the control arm.7. The assembly as recited in claim 6, wherein the portion of the cruisecontrol arm comprises a protuberance of the cruise control arm.
 8. Theassembly as recited in claim 1, wherein the cruise control arm isadapted to allow movement of the control arm in response to activationof a brake mechanism.
 9. The assembly as recited in claim 8, furthercomprising a return arm linked to the brake mechanism adapted to contactand move the control arm to the neutral position in response toactivation of the brake mechanism.
 10. The assembly as recited in claim9, further comprising a bearing mounted to the control arm and whereinthe return arm is adapted to contact the bearing to move the controlarm.
 11. The assembly as recited in claim 10, wherein the return arm hasa pair of angled surfaces each leading to a well for guiding the bearingto a position in the well in response to activation of the brakemechanism.
 12. The assembly as recited in claim 11, wherein the well isadapted to prevent movement of the bearing when the control arm is inthe neutral position and the brake mechanism is activated.
 13. Theassembly as recited in claim 1, further comprising a damper linked tothe control arm for controlling a rate of movement of the control arm.14. The assembly as recited in claim 1, further comprising a damperlinked to the return to neutral mechanism for controlling a rate ofmovement of the control arm.
 15. The assembly as recited in claim 1,wherein the cruise control arm is moveable to a position that avoidscontact with the control arm throughout a full range of motion of thecontrol arm.
 16. The assembly as recited in claim 6, wherein thefriction pack is adjustable to change the positioning of the cruisecontrol arm relative to the control arm.
 17. An assembly, comprising: ahydraulic pump; a hydraulic motor in fluid communication with thehydraulic pump; an axle shaft linked to and drivable by the hydraulicmotor; a swash plate; a control arm linked to the swash plate andmoveable to provide the swash plate with a plurality of non-discreteangular orientations with respect to the hydraulic pump; a return toneutral mechanism for moving the control arm from a driving position toa neutral position; and a cruise control arm moveable to a plurality ofnon-discrete positions having a portion occupying a plane in common witha portion of the control arm, wherein the cruise control arm is moveableto place the portion of the cruise control arm in contact with theportion of the control arm to prevent the control arm from moving fromone of a plurality of non-discrete forward driving positions to theneutral position under the influence of the return to neutral mechanism.18. The assembly as recited in claim 17, wherein the return to neutralmechanism comprises a biased return arm that contacts the control arm.19. The assembly as recited in claim 17, further comprising a frictionpack for frictionally engaging the cruise control arm with a forcesufficient to overcome a force applied to the control arm by the returnto neutral mechanism.
 20. The assembly as recited in claim 17, whereinthe portion of the cruise control arm comprises a generally flat surfaceof the cruise control arm.
 21. The assembly as recited in claim 17,wherein the portion of the cruise control arm comprises a protuberanceof the cruise control arm.
 22. The assembly as recited in claim 17,wherein the portion of the control arm comprises a protuberance of thecontrol arm.
 23. The assembly as recited in claim 22, wherein theportion of the cruise control arm comprises a protuberance of the cruisecontrol arm.
 24. The assembly as recited in claim 17, wherein the cruisecontrol arm is adapted to allow movement of the control arm in responseto activation of a brake mechanism.
 25. The assembly as recited in claim24, further comprising a return arm linked to the brake mechanism andadapted to contact and move the control arm to the neutral position inresponse to activation of the brake mechanism.
 26. The assembly asrecited in claim 25, further comprising a bearing mounted to the controlarm and wherein the return arm is adapted to contact the bearing to movethe control arm.
 27. The assembly as recited in claim 26, wherein thereturn arm has a pair of angled surfaces each leading to a well forguiding the bearing to a position in the well in response to activationof the brake mechanism.
 28. The assembly as recited in claim 27, whereinthe well is adapted to prevent movement of the bearing when the controlarm is in the neutral position and the brake mechanism is activated. 29.The assembly as recited in claim 25, wherein the braking mechanismcomprises a braking lever linked to the return arm which is linked to arotatable brake arm used to actuate a braking element associated with amotor shaft driven by the hydraulic motor.
 30. The assembly as recitedin claim 29, wherein the return arm is biased so as to rotate the brakearm linked to the return arm to a position wherein the brake element isun-actuated when the brake lever is moved to position corresponding toan un-actuated brake mechanism position.
 31. The assembly as recited inclaim 29, wherein the brake arm has an opening, a rod passes through theopening and is rotatably connected to and moveable with the return armto link the brake arm to the return arm, and a spring is associated withthe rod and positioned adjacent to the brake arm for applying a force torotate the brake arm in cooperation with the rod when the brake lever isactuated.
 32. The assembly as recited in claim 24, further comprising abypass mechanism for use in interrupting fluid communication between thehydraulic pump and the hydraulic motor and a bypass latch used to limitoperation of the bypass mechanism and moveable in response to activationof the brake mechanism.
 33. The assembly as recited in claim 31, furthercomprising a bypass mechanism for use in interrupting fluidcommunication between the hydraulic pump and the hydraulic motor and abypass latch used to limit operation of the bypass mechanism andmoveable in response to movement of the brake arm.
 34. The assembly asrecited in claim 33, wherein the bypass mechanism includes a rotatablebypass arm and the bypass latch includes a grooved portion for engagingan end of the bypass arm.
 35. The assembly as recited in claim 34,wherein the brake arm and the bypass latch are in cooperative alignmentsuch that rotation of the brake arm causes the bypass latch to rotateinto a position spaced from the bypass arm.
 36. The assembly as recitedin claim 17, further comprising a damper linked to the control arm forcontrolling a rate of movement of the control arm.
 37. The assembly asrecited in claim 17, further comprising a damper linked to the return toneutral mechanism for controlling a rate of movement of the control arm.38. The assembly as recited in claim 17, wherein the cruise control armis moveable to a position that avoids contact with the control armthroughout a full range of motion of the control arm.
 39. The assemblyas recited in claim 19, wherein the friction pack is adjustable tochange the positioning of the cruise control arm relative to the controlarm.
 40. The assembly as recited in claim 1, further comprising atrunnion arm linking the swash plate and the control arm.
 41. Theassembly as recited in claim 40, wherein the cruise control arm pivotsabout the trunnion arm.
 42. The assembly as recited in claim 17, furthercomprising a trunnion arm linking the swash plate and the control arm.43. The assembly as recited in claim 42, wherein the cruise control armpivots about the trunnion arm.